Furnace transfer mechanism



Nov. 23, 1965 N. J. ACKER FURNACE TRANSFER MECHANISM 2 Sheets-Sheet 1 Filed May 10, 1962 INVENTOR:

United States Patent 3,219,330 FURNACE TRANSFER MECHANISM Norman J. Acker, Meadville, Pm, assignor to Sunbeam Equipment Corporation, Meadville, Pa., a corporation of Delaware Filed May 10, 1962, Ser. No. 193,835 7 Claims. (Cl. 266-4) The present invention relates to heat treating apparatus, and more particularly to work transfer apparatus for use in a heat treating furnace.

The invention is concerned with the type of furnace in which a gas or atmosphere is maintained within the furnace during the heat treating cycle. At the end of the heat treating cycle, and prior to exposing the work to the air outside of the furnace, the work is quenched. It is desirable that the parts or work be maintained in the furnace atmosphere until they have been quenched, cooling the parts to a safe temperature. The problem solved by the instant invention relates to the transfer of the parts from the heat treating portion of the furnace to the quench tank while maintaining the furnace atmosphere.

The design of such a transfer mechanism is complicated by the high temperatures present within the heat treating enclosure. Any complex conveyors or mechanisms positioned within the heat treating enclosure and subjected to high temperatures would malfunction and cease to operate in a relatively short time. In Acker et al. US. Pat. No. 2,965,369 there is disclosed a transfer mechanism for heat treating apparatus in which reciprocating pusher members are employed to move work to be heat treated into the furnace and from the interior of the furnace into the quenching chamber. In this prior apparatus the portion of the transfer mechanism which advances the work from the heat treating enclosure to the quench chamber extended through an opening in the wall of the furnace enclosure. This portion of the transfer mechanism, which is termed a pusher element, reciprocated forwardly and backwardly to move the work through the furnace.

While such a mechanism was very satisfactory, there are instances in which it is necessary to maintain the furnace enclosure completely sealed from the outside atmosphere. The presence of any connecting member extending through the wall of the furnace at all times tends to make the sealing of the furnace enclosure diflicult.

It is therefore an object of the present invention to provide a transfer mechanism which requires no opening through the furnace wall.

It is a further object of the present invention to provide an improved transfer mechanism for a heat treating furnace wherein the mechanism is completely external of the furnace enclosure.

It is an additional object of the present invention to provide a work transfer device for a furnace which is insertable through an opening in the furnace door to move the work from the furnace enclosure into the quench chamber.

It is an additional object of the present invention to provide a furnace having an entrance door through which the work transfer member is insertable to advance the work from the heat treating chamber into the quench chamber.

Further objects and advantages of the present invention will become apparent as the following description proceeds and the features of novelty which characterize the invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

For a better understanding of the present invention reference may be had to the accompanying drawings in which:

FIG. 1 is a cutaway perspective view of a heat treatment apparatus showing the improved transfer mechanism of the present invention;

FIG. 2 is a sectional view taken along line 2-2 of FIG. 1; and

FIG. 3 is a fragmentary sectional view taken along line 22 of FIG. 1 showing the work transfer mechanism in its completely withdrawn position.

The present invention is concerned with a work transfer mechanism for use in a controlled atmosphere type of heat treatment apparatus. The transfer mechanism includes a longitudinally movable member which is adapted for insertion into the furnace enclosure to move parts contained therein from the furnace enclosure into the quench chamber while maintaining the atmosphere within the furnace enclosure during the transfer of work to the quench chamber. The entrance door for the furnace is provided with at least one small opening through which an elongated rod is insertable to engage the work in the furnace. This door for the furnace is movable between three different positions. These positions are, (1) an open position which it occupies during the loading of parts into the furnace enclosure, (2) a full closed position which it occupies during the heat treating cycle, and (3) an intermediate position wherein the door is partially raised to expose the openings through which the work transfer rod is inserted into the furnace. Through the use" of the multiple position door and the movable transfer rod insertable through the door, it is possible to maintain a very complete seal for the enclosure during the heat treating cycle and also a well sealed condition during the time when the work is transferred from the furnace enclosure to the quench chamber.

Referring now to the drawings, there is illustrated a heat treating furnace generally designated by reference numeral 11, which furnace is particularly adapted to heat treatment operations such as case harding, carborizing, carbonitriding and the like. The furnace includes a loading section 12, a heated enclosure 14, and a quench chamber 16. The heated enclosure 14 is conventional in all respects having a refractory insulating lining and suitable gas or electric heating means (not shown). The enclosure 14 is formed with an entrance opening 20 through which work is inserted into the enclosure and a discharge opening 22 through which work is unloaded from the furnace.

A vertically movable or slidable door 24 is provided to close the entrance opening 20. For the purpose of operating the entrance door 24 there is provided an air cylinder 26 having a reciprocating piston 28 which is connected to the lower edge of the door 24. The entrance door 24 is formed with a thick insulating portion 24a which is a suitable size to close the entrance opening 20 in the furnace enclosure. At the lower edge of the door 24 and beneath the thick insulated portion 24a, there is provided a flange 24b which is of reduced thickness. Extending through the flange 24b are two openings 24c. Connected to the flange 24b and aligned with the outer ends of openings 240 are funnel-like members 24d.

In normal operation, the door 24 is positioned in any one of three different positions. In the opened position, not shown in the drawings, the door is moved upwardly until the lower flange 24b is above the upper edge of the entrance opening 20. This permits the insertion of the maximum size parts as will be accommodated by the opening 20. In FIG. 3 the door 24 is shown in its lowered position in which the thick insulated portion 24a is completely covering the opening 20. The door 24 is located in this position throughout the heat treating cycle so as to obtain maximum insulation and sealing. In FIGS. 1 and 2 the door 24 is shown in its intermediate position, the purpose of which will be explained in greater detail below.

The loading section 12 includes a frame 12a which supports -a horizontally extending roller conveyor 12b. Trays of parts, or the parts themselves, may be placed on the conveyor 12b and slid through the entrance opening into the heated enclosure 14.

The frame 12a also serves to support the work transfer mechanism which includes a motor and gear reduction unit 32. The output of the motor and gear reduction unit 32 is connected by means of a chain or link belt 34 to a drive sprocket 36. The drive sprocket 36 is mounted on a transversely extending shaft 38 which is supported by suitable bearings or pillow blocks on the frame 12a. Positioned inwardly of the bearings for the shaft 38 are belt sprockets 40 which drivingly engage a pair of horizontally extending flexible carrier members which may take the form of chain belts 42 and 44. The ends of the chain belts 42 and 44 remote from the drive sprocket 36 are supported by a second transverse shaft 46 and suitably mounted sprockets 48 and 50. It should be understood, therefore, that the motor and gear reduction unit 32 is connected to drive the chain belts 42 and 44.

Extending horizontally above each of the chain belts 42 and 44 are push rods or work transfer rods 52 and 54, respectively. The outer ends of the rods 52 and 54 are formed with flattened portions 52a and 54a, respectively, which may serve to engage limit switches controlling the forward and backward movement of the rods. The flatted end portions 52a and 54a are connected by means of links 56 to the respective chain belts 42 and 44. As may best be seen in FIG. 1 the links 56 straddle the end portions 52a and 54a and employ a transversely extending pin 56a to pivotally interconnect the links with the rods 52 and 54. The lower ends of the links 56 are suitably secured to the chain belts 42 and 44. The links 56 drivingly interconnect the belts 42 and 44 with the work transfer arms 52 and 54 so that as the belts are set in motion the work transfer arms move horizontally into or out of the furnace enclosure 14. The motor and gear reduction unit 32 is reversible so that the chain belts 42 and 44 may be moved in either direction.

It should be noted that the work transfer rods 52 and 54 as well as their driving belts 42 and 44 extend parallel to and along side the roller conveyor 12b. The rods 52 and 54 cannot be above the level of the roller conveyor 12b during the time when work is being loaded into the furnace 14. When the rods 52 and 54 are operative to move material through the furnace, they are raised above the level of the conveyor 12b in the manner to be described below.

Referring to FIG. 2,- the arrangement of the heated enclosure 14 and the quench chamber 16 is shown. The quench chamber 16 has a quench tank 16a positioned at the bottom thereof and an elevator mechanism 16b by means of which the parts may be lowered into the quench liquid located in the quench tank 16a. An opening 16c is formed in the quench chamber 16 in alignment with the discharge opening 22 in the enclosure 14. To seal the exit or discharge opening 22 from the enclosure 14, there is provided a discharge opening door 58 which is located between the enclosure opening 22 and the quench chamber opening 160. The door 58 is operated by means of a suitable cylinder 59. There is also an opening 16d through which parts may be removed from the quench chamber. A door 60 is mounted for slidable movement by means of a cylinder 61 to seal the discharge opening 16d from the quench chamber.

In considering the operation of the heat treating furnace 11, it should be understood that the sequence of operations may be performed manually, or as is more conventional, by appropriate cycle timers and limit switches. inasmuch as the sequential automatic control of the various parts of the furnace does not form any part of the specific invention, the control circuits and mechanisms have not been disclosed therein. At the beginning of the heat treating cycle, the entrance door cylinder 26 is operated to raise the entrance door 24 to permit insertion of a tray of parts into the heated enclosure 14. The tray of parts is shown in dotted form in FIGS. 1 and 2 and designated by reference numeral 62. The parts tray 62 may be of any suitable size so that it may be received in the furnace enclosure 14. It must be wider than the spacing of the work transfer rods 52 and 54 so that both of the rods may engage the end of the tray and move it through the furnace. After the tray 62 has been placed within the enclosure 14, the door 24 is lowered to the position shown in FIG. 3 wherein the thick insulated portion 24a completely closes the entrance opening 20 of the heated enclosure 14. It should be noted that in the door position shown in FIG. 3, the openings 240 through the flange 24b are positioned out of alignment with the opening 20 and therefore are not in communication with the interior of the heated enclosure 14. To further seal the openings 24c, there may be provided asbestos webbing fastened at the lower edge of the insulated portion 24a and draped across the funnels 24d.

As was mentioned above, the work transfer rods 52 and 54 in their retracted position as shown in FIG. 3 are below the level of the roller conveyor 12b, thus permitting the conveyor to support the parts tray 62 for movement into the furnace. As may best be seen in FIG. 3, the links 56 which interconnect the belts 42 and 44 with the wo k transfer rods 52 and 54 respectively are inclined rearwardly at an angle of approximately 45 degrees. This inclination is caused by the fact that the links have moved around the ends of the belt sprockets 40. This positioning of the links 56 results in the outer ends of the work transfer rods 52 and 54 being lowered below the level of the roller conveyor 12b. For the work transfer rods 52 and 54 to be effective in moving the parts tray 62 through the furnace enclosure 14, it is necessary that they be raised to a level above that shown in FIG. 3 whereby their ends engage the tray 62. This raising of the work transfer rods 52 and 54 is accomplished in part by the links 56 moving to a vertical position thereby lifting the rear ends of the rods. The forward ends are raised by virtue of their engagement with the funnels 24d having ramp-like lower edges, as may be seen in FIG. 2.

At the end of the heat treatment cycle, the air cylinder 26 is actuated to move the door 24 to the position shown in FIGS. 1 and 2, at which position the funnels 24d and the openings 240 are located in substantial axial alignment with the push rods or work transfer arms 52 and 54. At the same time the door 24 is moved to the position shown in FIG. 2, the door 58 is moved to an elevated position by cylinder 59 to permit removal of the parts from the heated enclosure 14. The motor and gear reduction unit 32 is then energized to rotate the drive sprocket 36 in a clockwise direction as viewed in FIGS. 1 through 3. The work transfer arms 52 and 54 then move from the position shown in FIG. 3 through the openings 240 in the door 24 in a manner shown in FIG. 2. In comparing the relative positions of the work transfer rod 54 and the roller conveyor 12b as shown in FIGS. 2 and 3, it may be noted that the rod 54 is raised from its position sup ported by the belt 44 to a position several inches higher as it moves forward as shown in FIG. 2. As was mentioned above, the link 56 has moved from an inclined to a vertical position and the front end of the rod has been biased upwardly by the funnel 24d as it enters the opening 246. The two worktransfer arms then engage the tray 62 pushing it horizontally through the discharge opening 22 in the heated enclosure 14 and into the quench chamber 16 to a position on the elevator mechanism 161).

The elevator mechanism 16b may then be actuated lowering the parts in the tray 62 into the quench tank 16a. It may be appreciated that with the door 24 moved to the position shown in FIG. 2 and the quench chamber 16 sealed by the exit door 60, the parts contained in the basket 62 are maintained in the furnace atmosphere while they are moved from the enclosure 14 into the quench tank 16a. Applicants transfer mechanism provides a simple means of transferring the parts in a sealed enclosure while at the same time utilizing a mechanism which is located completely outside of the heated area of the furnace.

While there has been shown and described a particular embodiment of the invention, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention, and that it is intended by the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. Heat treating apparatus comprising an enclosure having an entrance opening therein, a door slidably movable between an open position and a closed position sealing said opening, said door having a lower flange portion through which at least one hole extends, said hole being closed by the wall of said enclosure when said door is in the closed position, said door being movable into an intermediate position in which it covers said entrance opening and in which said hole is in alignment with said entrance opening, a work transfer mechanism located completely outside of said enclosure and positioned adjacent said entrance opening and including a work engaging portion in operative alignment with said entrance opening insertable through said hole and said opening when they are aligned with said door in said intermediate position of said furnace.

2. Heat treating apparatus as set forth in claim 1 wherein said work engaging portions are mounted for reciproeating movement, and funnel means are connected to said flange to guide said work engaging portion into said hole.

3. A heat treating furnace comprising a sealed enclosure having an opening through which material to be heated may be introduced into the enclosure; a slidably mounted door for said opening movable between an open position, a closed position sealing said opening, and an intermediate position; said door having at least one opening formed therein which opening is aligned with the enclosure opening when said door is in said intermediate position and sealed by a fixed wall portion of said furnace when said door is in closed position; and transfer means mounted outside of said enclosure opening in operative alignment therewith and including means insertable through the opening in said door when in the intermediate position to move said material while maintaining said enclosure sealed.

4-. Heat treating apparatus comprising a sealed heated enclosure having a work entrance opening and a work discharge opening, independently operable entrance opening and work discharge opening doors movable between open nonobstructing positions and closed positions sealing said openings, a quench chamber in communication with said discharge opening, a reciprocating work advancing means mounted completely outside of said work entrance opening, said work advancing means including an elongated member insertable through said entrance opening to move Work from said enclosure into said chamber through said discharge opening, said entrance opening door having at least one door opening through which said elongated member may be inserted, said door opening being sealed by a fixed portion of said furnace when said entrance opening door is in the closed position, said entrance opening door being movable to an intermediate position in which said door opening is aligned with said entrance opening and said work advancing means.

5. Heat treating apparatus comprising a furnace enclosure having a work entrance opening, a roller conveyor aligned with said opening for supporting material being moved into said furnace enclosure, a pair of spaced driven elongated flexible carrier members extending parallel to said conveyor on either side thereof, reversible drive means for said members, material transfer rods connected at their outer ends to said members for movement therewith, said rods being movable between a retracted position adjacent said roller conveyor and an operative position extending through said opening into said furnace, said rods in the retracted position being below the level at which said material is supported on said roller conveyor, said members moving the outer ends of said rods upwardly to positions above said level upon movement from said retracted positions a door for said opening having apertures therein horizontally aligned with said members and Positioned above said level, means adjacent said apertures biasing said rods upwardly above said level upon movement into said apertures for engagement with material within said furnace enclosure.

6. Heat treating apparatus as set forth in claim 5 having vertically extending links interconnecting the outer ends of said rods to their respective carrier members, said links being inclined only in the retracted position of said rods to lower said rods below said level and moving to a vertical position to support said rods above said level when said rods are advanced into said furnace.

7. Heat treating apparatus as set forth in claim 5 wherein said apertures are sealed by a fixed portion of said furnace when said door is in the closed position, said door being movable to an intermediate position in which it completely covers said entrance opening and said apertures communicate with the interior of said furnace through said entrance opening, said rods being insertable into said apertures when said door is in said intermediate position.

References Cited by the Examiner UNITED STATES PATENTS 1,818,759 8/1931 Schrumn 263-6 2,965,369 12/1960 Acker et a1 266--4 3,104,768 9/1963 Bassett 2 l423 WHITMORE A. WILTZ, Primary Examiner.

DELBERT E. GANTZ, MORRIS O. WOLK, Examiners. 

1. HEAT TREATING APPARATUS COMPRISING AN ENCLOSURE HAVING AN ENTRANCE OPENING THEREIN, A DOOR SLIDABLY MOVABLE BETWEEN AN OPEN POSITION AND A CLOSED POSITION SEALING SAID OPENING, SAID DOOR HAVING A LOWER FLANGE PORTION THROUGH WHICH AT LEAST ONE HOLE EXTENDS, SAID HOLE BEING CLOSED BY THE WALL OF SAID ENCLOSURE WHEN SAID DOOR IS IN THE CLOSED POSITION, SAID DOOR BEING MOVABLE INTO AN INTERMEDIATE POSITION IN WHICH IT COVERS SAID ENTRANCE OPENING AND IN WHICH SAID HOLE IS IN ALIGNMENT WITH SAID ENTRANCE OPENING, A WORK TRANSFER MECHANISM LOCATED COMPLETELY OUTSIDE OF SAID ENCLOSURE AND POSITIONED ADJACENT SAID ENTRANCE OPENING AND INCLUDING A WORK ENGAGING PORTION IN OPERATIVE ALIGNMENT WITH SAID ENTRANCE OPENING INSERTABLE THROUGH SAID HOLE AND SAID OPENING WHEN THEY ARE ALIGNED WITH SAID DOOR IN SAID INTERMEDIATE POSITION OF SAID FURNACE. 